Known magnetic tape cassettes comprise a generally rectangular housing which rotatively supports within the housing a pair of roll cores that are aligned parallel to the working edge of the housing which is formed with an aperture for receiving the magnetic head of an associated cassette drive. The opposite ends of a length of tape are wound around the two roll cores and an intermediate stretch of tape is positioned by guide rollers just inside the working edge so that it can be engaged by the magnetic head projecting into that aperture. The cassette cores contain sprocket holes which are engaged by the spindles of the cassette drive which rotate the two cores in one direction or the other so that the tape is moved past the head and wound up on one roll core or the other.
A problem has arisen due to the formation of slack tape loops or twists within the housing which can become caught by and wound onto the winding roll core. This tends to stop the tape advance and/or cause the tape to break. In some cases, the cassette can be taken apart and the tape repaired; but in many instances the cassette cannot be so repaired and is just thrown away.
The aforesaid jam-forming slack tape loops are not formed, in the main, when the cassette is in operation. Rather, they arise when the cassette is being handled. In other words, someone might turn one of the roll cores by its sprocket hole so as to unroll the tape and form a tape loop or loops within the cassette housing. In some instances, such slack tape might engage the outermost tape turn on one of the roll cores. If, when the cassette is next used, that roll core is rotated in the winding direction, the slack tape can be caught by the tape winding onto that core. The engaged loop tends to pull the tape in the opposite direction around the tape guide rollers causing a tape break or the winding roll core becomes jammed, resulting in damage to the cassette and sometimes even to the associated tape cassette drive. The same problem can arise when an operator ejects the cassette from the cassette drive while the tape is advancing. In this case, the slack tape condition in the cassette is due to the residual inertia of the unwinding tape roll.